1. Field of the Invention
The present invention relates to sliding drawer guide comprising a guide rail substantially forming a U-section, a drawer rail which is supported on a track roller in the front end portion of the guide rail and in the rear end portion carriers a track roller rolling on a lower guiding web of the guide rail, and can be prolonged by a pivoted supporting lever beyond the rear wall of the drawer, as well as a guide bracket provided in the rear end portion of the mounting flange of the guide rail for the supporting lever. The lever can be swivelled between an upper rest position and a lower, stop-limited working position, and in the vicinity of its free end accommodates a guiding member engaging in the guide bracket and a supporting roller coopering with an upper guiding web of the guide rail.
2. Description of the Prior Art
To be able to fully draw out the drawers without having to provide an intermediate rail between the guide rail and the drawer rail of a sliding drawer guide, it is known (DE-29 46 113A1) to pivotally mount in the rear end portion of the drawer rail a supporting lever which can be swivelled from an upper rest position into a lower, stop-limited working position, so that the drawer rail is prolonged by this supporting lever when the drawer is drawn out. Since the supporting lever may carry a supporting roller in the vicinity of its free end, and the drawer rail may carry a track roller in its rear end portion, the drawer rail may be guided between the two legs of the guide rail U-shaped in cross-section, which legs form an upper and a lower guiding web for the supporting roller and the track roller, where the web connecting the two legs constitutes a mounting flange. The drawer rail Z-shaped in cross-section additionally rests on a track roller supported in the front end portion of the guide rail above the upper guiding web, which track roller takes away part of the weight of the drawer. By means of the rear track roller of the drawer rail the remaining load is carried away to the guide rail, as long as the center of gravity of the drawer lies behind the track roller of the guide rail. When upon drawing out the drawer, the center of gravity of the drawer is shifted by means of the track roller of the guide rail, the supporting roller of the supporting lever resting against the upper guiding web prevents the drawer from tilting, which can thus be drawn out until the track roller of the drawer rail reaches the end of the guide rail. Since the track roller of the guide rail is disposed above the upper guiding web, the two track rollers of the guide rail and the drawer rail can lie one above the other, when the drawer has been fully drawn out. To ensure that the supporting lever can be swung up from its working position into the rest position when the drawer is pushed in, the guide rail constitutes a guide bracket for the supporting lever in the rear portion of the mounting flange prolonged beyond the upper guiding web, which supporting lever engages into the guide bracket by means of a guiding pin laterally protruding against the guide bracket. The main disadvantage of this known drawer slide is the fact that due to the guide rail extending laterally beside the drawer, a comparatively large gap must be provided between the side walls of the drawer and the inner wall of the cabinet, so that the possible drawer width is limited. In addition, the fastening screws for the guide rail are disposed between the two guiding webs, so that there is a risk that in the case of an inclined fastening screw or a fastening screw not fully screwed in, the head thereof might protrude into the path of movement of the track roller or the supporting roller of the drawer rail.
To achieve a large drawer width it is already known (DE 94 13 108 U1) to provide the guide rail below the drawer between the front and the rear face wall of the cabinet, and to dispose the drawer rail on the bottom surface of the drawer beside the guide rail. Apart from the fact that with this known construction a significant torsional stress is applied onto the rails, such sliding drawer guide does not allow to fully draw out a drawer, as the rear track roller of the drawer rail must not be moved up to the front track roller of the guide rail, so as to prevent the drawer form tilting forward.